#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <numeric>
#include <functional>
#include <cmath>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <sstream>
#include <string>

#define repd(i,a,b) for (int i=(a);i<(b);i++)
#define rep(i,n) repd(i,0,n)
#define var auto
#define mod 1000000007
#define inf 2147483647
#define nil -1
typedef long long ll;

using namespace std;

inline int input(){
    int a;
    cin >> a;
    return a;
}

template <typename T>
inline void output(T a, int p) {
    if(p){
        cout << fixed << setprecision(p)  << a << "\n";
    }
    else{
        cout << a << "\n";
    }
}

// end of template

int main() {
    cin.tie(0);
    // source code
    int N;
    ll M;
    cin >> N >> M;
    
    vector<ll> f(80);
    
    f[0] = f[1] = 1;
    
    repd(i, 2, 80){
        f[i] = f[i - 1] + f[i - 2];
    }
    
    int cnt = 0;
    
    M = f[N - 1] - M;
    
    //output(M, 0);
    
    for (int i = N - 3; i >= 0; i--){
        if (M >= f[i]) {
            M -= f[i];
            cnt++;
        }
        if (M == 0) {
            break;
        }
    }
    
    output((M == 0) ? cnt : -1, 0);
    
    return 0;
}